Peltier-cooled sample stage

Von Seggern, C. E. Gardner, B. D. Cotter, R. J. Infrared atmospheric pressure MALDI ion trap mass spectrometry of frozen samples using a Peltier-cooled sample stage. Anal. Chem. 2004, 76, 5887-5893. 

Figure 3.17. Scheme of the wet-STEM imaging mode, a Peltier cooling stage b TEM-grid type sample holder c annular detector for transmitted electrons collection i incident electron beam. 

For frozen samples Peltier cooling stage (e.g., Ferrotec Corp., Bedford, NH, USA) with heat fan (e.g.. Allied Electronics, Inc., Eort Worth, TX, USA), and DC power supply. 

The Peltier heating/cooling stage allows working within 20 °C above or below ambient temperature, and the combination of low temperature (e.g., 4 °C) and high water vapor pressure (e.g., 6.1 Torr) permits achievement of 100% relative humidity (RH) at the sample surface. At 100% RH, samples are not dehydrated during the imaging process. At less than 100% RH, a moist sample constantly loses water as the vacuum in the chamber pumps on it in the scope, it appears as constant movement of the sample. 

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